docs: add note about compilers with modules (#9520)
docs: add note about compilers with modules (#9520)

compilers.yaml can track a module that is needed for a compiler, but
Spack does not fill this in automatically. This adds a note to the
documentation informing the user how to do this.
iulian787/spack,iulian787/spack,iulian787/spack,LLNL/spack,LLNL/spack,LLNL/spack,iulian787/spack,LLNL/spack,iulian787/spack,LLNL/spack